Polyurethane Acrylate Research Articles

Synthesis and characterization of UV curable polyurethane acrylate derived from α-Ketoglutaric acid and isosorbide

A thermally stable coating of UV curable polyurethane acrylate (PUA) was prepared from bio-based PU and methyl 3-(4-hydroxy-3-methoxyphenyl)acrylate(MHPA). The presence of the aromatic ring in the backbone associated with MHPA imparts thermal stability in the structure. The bio-based PU was prepared through the condensation polymerization of hexamethylene diisocyanate(HDI) and a polyol prepared by the condensation reaction of α-ketoglutaric acid(KA) with isosorbide(IS). Isosorbide and α-ketoglutaric acid represent the replacement of the petroleum-based precursors used in polyol synthesis. Characterization of the new compound has been carried out using Fourier transform infrared spectroscopy(FT-IR) and nuclear magnetic resonance spectroscopy(NMR) and correlated with the quantitative analysis through hydroxyl and acid value. The UV curable PUA was added into the commercial polyurethane acrylate(CPUA) coating system and assessed based on their functional properties. The flexibility of the cured coating was determined by understanding the glass transition temperature through differential scanning calorimetry(DSC). Thermal gravimetric analysis was used to measure the thermal stability of the PUA and CPUA mixture. With an increase in the concentration of PUA, the thermal stability of the mixture improves. The structure of the prepared coating has been assessed using X-ray diffraction methods. The dynamic mechanical properties such as storage and loss modulus of the coating were determined from the rheological behavior. The mechanical properties and chemical/solvent resistance of the mixture were calculated and correlated with the gel content and moisture content. The nature of the fracture of the coating was observed through scanning electron microscopy(SEM).

UV LED curable epoxy soybean-oil-based waterborne PUA resin for wood coatings

An environmentally friendly waterborne wood coating with a rapid curing speed and good mechanical properties was investigated. Acrylated epoxidized soybean oil (AESO) and pentaerythritol triacrylate (PETA) were introduced to a UV-curable waterborne polyurethane acrylate (PUA) resin, which realize the fast curing of the coating under a 395-nm UV LED light source. The emulsion and film were characterized by particle size, FTIR, 1H-NMR and the mechanical properties. The result showed that the mechanical properties of the film were optimal with AESO content 45%, which tensile strength, elongation at break and modulus of elasticity were 27.53 MPa, 26.35%, and 293.62 MPa, respectively. The particle size of the emulsion was smaller than 50 nm. It displayed a good stability and a uniform distribution. The glass transition temperature was 123.3 °C. The hardness, the adhesion force, the water absorption rate, the gloss and the abrasion loss were 6H, Level 1, 9.9%, 22.1°, and 0.002 g, respectively. After pre-drying and UV LED irradiation, the wood coating cured quickly in a short time. The epoxy soybean-oil-based waterborne PUA resin indicated highly promising in the field of wood coatings.

Facile synthesis and characterization of renewable dimer acid-based urethane acrylate oligomer and its utilization in UV-curable coatings

A UV-curable polyurethane acrylate (PUA) oligomer was prepared from dimer acid (DA) based polyester polyol (DAPEP) with a monofunctional acrylate precursor which was developed upon isophorone diisocyanate (IPDI) reacted with 2-hydroxyethyl methacrylate (HEMA). The structural elucidation of synthesized dimer acid based PUA (DAPUA) oligomer was verified through Fourier-transform infrared spectroscopy (FT-IR) and Proton nuclear magnetic resonance (1H NMR). A series of UV cured coatings were prepared by adding trimethylolpropane triacrylate (TMPTA) and 1,6-hexanediol diacrylate (HDDA) reactive diluents in varying percentages (10−30 wt%) to PUA oligomer. The bio-coatings exhibited exceptional results, including the highest thermal degradation temperature of 382–422 °C, glass transition temperature (Tg) of 56.38–66.27 °C, the tensile strength of 17.3–30.6 MPa, volume shrinkage of 6.19–9.13 %, and surface roughness of 4.89–28.21 nm. Compared to vegetable oil based UV-curable coatings, long chain dimer acid based PUA oligomer coatings exhibited excellent flexibility, impact, hydrophobicity, and resistance to volume shrinkage.

Thermal Decomposition Kinetic Analysis and Performance Characterization of Low Dk/Df Ink based on Polyurethane Acrylate

Thermal Decomposition Kinetic Analysis and Performance Characterization of Low Dk/Df Ink based on Polyurethane Acrylate

Research on the Performance of Series Waterborne Polyurethane Acrylate Modified Epoxy Acrylates

In this study, a series of bifunctional-based UV curable waterborne polyurethane acrylate modified epoxy acrylate (UV-WPUA) was prepared by using 2,4-toluene diisocyanate (TDI), Epoxy resin (E51) and polyethylene glycol (PEG) as the main materials. Waterborne resin and UV curing film with content of C-O-C were obtained by using polyethylene glycols with different molecular weights. The infrared spectra (FT-IR) demonstrated the presence of C=C and epoxy bond in the UV curing film chains. In addition, the molecular weight of the oligomer, and glass transition temperature, gelation rate and thermogravimetric analysis of the films were investigated.

Photo-crosslinked coatings from an acrylate terminated non-isocyanate polyurethane (NIPU) and reactive diluent

Non-isocyanate polyurethane acrylate coatings (NIPUAs) were prepared by photocrosslinking of mixtures of an acrylate terminated NIPU oligomers (A-Ol) and reactive (meth-)acrylate diluents. A-Ol were prepared by a transurethane polycondensation pathway followed by an acrylation reaction of the resulting hydroxy chain-ends. The influence of the reactive diluent content and chemical structures on the thermal and mechanical properties of these coatings has been investigated. The obtained materials exhibited thermal stabilities above 255 °C, Young modulus ranging from 2.6 to 9.2 MPa, tensile strength from 2.69 to 25.5 MPa and elongation at break from 56 to 470%.

Non-edible oil based polyurethane acrylate with tetrabutylammonium iodide gel polymer electrolytes for dye-sensitized solar cells

Polyurethane acrylate (PUA) gel polymer electrolytes were prepared with tetrabutylammonium iodide (TBAI) as the complex salt. Fourier transform infrared spectroscopy results confirmed that the NH, CO, CN and COC polar functional groups formed the coordination with TBA+ cations of salt observed from the bands shift. The maximum ionic conductivity of (1.88 ± 0.02) × 10-4 S cm−1 was obtained for the electrolyte with composition of 67.94 wt% PUA–30.00 wt% TBAI–2.06 wt% I2 (S3 electrolyte) which influenced by the highest charge mobility of (6.24 ± 0.12) × 10-7 cm2 V−1 s−1 and number density of (1.93 ± 0.04) × 1021 cm−3 estimated from fitting the Nyquist plots. The S3 electrolyte was electrochemically stable up to 1.64 V and capable of performing up to 2000 cycles steadily. Triiodide ion diffusivity obtained was 1.70 × 10-8 cm2 s−1. The electrolyte performance in dye-sensitized solar cells (DSSCs) was tested and cell with S3 electrolyte showed the highest solar conversion efficiency of (1.97 ± 0.21)% with short-circuit current density (Jsc) of (7.15 ± 0.74) mA cm−2 and open-circuit voltage (Voc) of (0.55 ± 0.01) V when exposed under 1000 W m−2 light illumination. The highest efficiency obtained was influenced by the high electrons driving force in DSSCs. Low reduction resistance (Rpt) of (2.46 ± 0.08) Ω at the electrolyte/counter electrode interface along with low charge transfer resistance (Rct) of (24.97 ± 0.14) Ω at TiO2/dye/electrolyte interface and charge diffusion resistance (Rd) of (34.14 ± 0.11) Ω in redox electrolyte increase the electrons dynamic, thus resulting high Jsc and hence high DSSC efficiency. This work shows that PUA-based electrolytes have potential for DSSC applications.

Preparation and properties of UV-curable diamine-based polyurethane acrylate hard coatings

Three polyurethane acrylate (PUA) branched compounds with different diamines (Norbornane dimethylamine, piperazine and ethylenediamine) were synthesized under the facile reaction condition. Coatings based on synthesized branched compounds were prepared under UV-irradiation, and used as hard coatings to protect the plastic surface. The structures of PUA branched compounds were characterised by proton nuclear magnetic resonance and gel permeation chromatography. The effect of rigid diamines on the properties of coatings was investigated regarding to the curing behaviour, dynamic mechanical property, mechanical property and coating surface property. The results indicate that the final double bond conversion is associated with the rigidity of the diamines and the viscosity of the prepared coating solution. The rigid diamine endows the coating with high Tg value, and leads to phase separation that creates rough coating surface. The tensile test shows that the coating with highest crosslinking and moderately rigid diamine possesses excellent mechanical property with 20.7 MPa in tensile strength and 6.8% in elongation at break. The pencil hardness of the prepared PUA-PZ coating can reach to 5H that is higher than the commercially available resin PUA-6, and this coating also shows good adhesion and flexibility, which has potential to be applied as protective coating to protect PC surface well. Moreover, all coatings exhibit good thermal properties.

High-performance UV-curable Polyurethane Acrylate Resins Derived from Low-iodine Woody Plant Oils

In this study, we report the preparation of high-performance UV-curable polyurethane acrylate (PUA) materials from two low-iodine woody plant oils, rubber seed oil (RSO) and wilsoniana seed oil (WSO). First, high-functionality oil-based PUA oligomers were synthesized via isocyanate polyurethane reaction between hydroxylated woody plant oils, isophorone diisocyanate, and pentaerythritol triacrylate, in which the hydroxylated oils were obtained by ring opening of epoxidized oils with ethylene glycol. Chemical structures of the obtained RSO-based and WSO-based PUA oligomers (RSO-PUA and WSO-PUA) were confirmed by FT-IR and 1H NMR. The 1H NMR results indicated that the RSO-PUA and WSO-PUA oligomers reached a C = C functionality up to 20.9 and 15.2 per triglyceride, respectively. The obtained oil-based PUA oligomers were then blended with hydroxyethyl methacrylate (HEMA) to form UV-curable resins and ultimate properties of the resultant materials were investigated. The oil-based PUA materials showed excellent performance after UV-curing. For example, the RSO-based PUA film containing 30% of HEMA demonstrated the tensile strength of 22.2 MPa, tensile modulus 1.78 GPa, glass transition temperature of 118.1 °C, adhesion of 2 grade, pencil hardness of 2H, and flexibility of 2 mm. In general, the developed woody plant oil-based PUA resins are very promising to be applied as green UV-curable coatings.

Photo-crosslinked Non-Isocyanate Polyurethane Acrylate (NIPUA) coatings through a transurethane polycondensation approach

A transurethane polycondensation pathway has been used to produce acrylate terminated Non-Isocyanate PolyUrethane (NIPUA) oligomers (A-Ol) with controlled molecular weights and chemical structures. These compounds were then photo-crosslinked under UV radiations to afford several NIPU acrylate coatings. The influence of the content in urethane functions as well as the chemical structures on the thermal and mechanical properties of the final coatings has been demonstrated. The obtained coatings exhibited thermal stabilities above 255 °C, Young modulus ranging from 2.6 to 9.2 MPa, tensile strength up to 11.8 MPa and elongation at break varying from 20 to 520%.

Large scale roll-to-roll production of polyurethane-acrylate-based hydrophobic film: a next-generation protection layer for solar devices

In the present study, we fabricate a hydrophobic film using a roll-to-roll technique capable of large-area continuous production and examine the film’s applicability to solar panels. The hydrophobic film was fabricated using a polyurethane-acrylate (PUA)-based UV-curable material, which has high optical transmittance and high releasability. The roll-to-roll system used in this study was custom manufactured to transfer micro-patterns of 20 μm in size onto the PUA-based film. In addition, a UV irradiation device was attached to the system to enable production of the hydrophobic film at a rate of 150 mm min-1. Through experiments, we confirmed that attaching the fabricated hydrophobic film not only enabled surface self-cleaning on the solar panels, but also ensured stable solar power generation. Thus, the hydrophobic film can be applied to installations that require external periodic cleaning and management, such as the exterior walls of buildings and solar panels.

High dielectric constant UV curable polyurethane acrylate/indium tin oxide composites for capacitive sensing

Taking into consideration environmental issues and additive manufacturing technologies, the development of advanced UV curable polymers and polymer composites is an area of increasing interest. In this scope, polyurethane acrylate (PUA) composites with Indium Tin Oxide (ITO) were produced in order to tune morphology, optical, thermal, mechanical and dielectric properties. It is shown that ITO particles are well dispersed within the polymer matrix and that the polymerization rate and the UV curing conversion degree are influenced by the ITO content. Moreover, the optical transparency has decrease to 20% for the samples containing 10 wt% ITO content and the elastic modulus increases 10% for same sample. On the other hand, the glass transition temperature of PUA is independent of the ITO amount. ITO/PUA composites with 25 wt% ITO filler content presents high dielectric constant of 33. This composite has been used for developing a capacitive sensor, showing the suitability of the UV curable materials for capacitive sensing applications.

Synthesis and properties of UV-curable polyurethane acrylates with reactive silicones

Over the past few years, silicone-based polymers have been widely studied because silicone shows unique surface properties, such as hydrophobicity, film formability, etc and then silicone-based compounds are being mainly applied to the coating field. To have these characteristics in coatings, it is crucial that silicone component participates in covalent bonding. In this research, UV-curable polyurethane acrylates (PUAs) with different molecular weights and contents of reactive silicones were synthesized to improve the surface and mechanical properties of coating films. The synthesized PUAs were identified with FT-IR spectra and the mechanical properties of the cured PUAs films were investigated by UTM. The water contact angle of the cured PUAs was measured by the drop shape analyzer and the gloss values of PUAs were measured by a gloss meter. Finally, the optimum content of reactive silicones in the PUAs was obtained.

Synthesis and photo-curing properties of polyurethane acrylates with difunctional acrylate

Although a photo curing is more efficient in terms of time, solvent, and cost than a thermal one, photo-curable coatings require low viscosity and fast curing speed due to workability and time saving, respectively. A high viscous oligomer with multi-acryl groups is one of main components to determine its physical property after curing and then viscosity of coatings is controlled by adding a diluent. The polyurethane acrylates were newly synthesized by using ethylene diamine as a chain extender in poly(ε-caprolactone) polyol, dicyclohexylmethane 4,4′-diisocyanate, and isocyanato acrylate (ICA) containing diacrylate and diisocyanate groups. IR spectra were used to identify the synthesis and photo curing process. The mechanical properties of the cured films were analyzed by UTM. The results showed that the tensile strength of the UV-cured films was depended on the ICA content in the polyurethane acrylates.

Preparation and properties of photo-curable coatings based on synthesis of self-photocuring polyurethane acrylate oligomer for pre-coated metal

In this study, we synthesized a self-photocurable intermediate by Michael addition reaction and synthesized a polyurethane acrylate oligomer. Photo-curable coatings were prepared by mixing the synthesized oligomer and HDDA/TMPEOTA ratio with a reactive diluent. The films were coated onto glass plates and base treatment metal plates using bar coaters with thicknesses of 120 μm and 30 μm, respectively. The mechanical properties increased with increasing crosslink density. The pencil hardness test was the best when the TMPEOTA content was 6 or 8 wt%, and the adhesion and banding test showed excellent physical properties when the TMPEOTA content was less than 10 wt%. MEK rubbing was all excellent.

Preparation and properties of UV-curable polyurethane-acrylate coatings of pre-coated metal (PCM): effect of polyol type/contents on adhesive property

Since UV curing coatings form a coating film with low adhesive property, it is difficult to use it as a coating for pre-coated metal (PCM) of post-processing method which has been actively studied recently. In this study, to apply UV-curing type coatings to pre-coated metal (PCM), which is applied as a method to improve productivity and to shorten the coating process, urethane acrylate oligomers were synthesized by using the content of polycaprolactone diol and hydrogenated polybutadiene glycol as a soft segment. UV-curable polyurethane acrylate coatings were prepared by varying the kind and content of the reactive diluent (IBOA, TMPEOTA). The urethane-acrylate oligomer and the coatings were well-prepared and confirmed using FT-IR. The storage modulus at RT, tensile strength and modulus were the highest values and the elongation at break was low. Also, as TMPEOTA content increased, the Tg of hard segment and storage modulus at RT, tensile strength and modulus increased, but elongation at break decreased. The surface free energy of all coating films was lower than that of metal plate. And the adhesive property of coatings using HPBD polyol of 30 and 50 mole% was the best and pencil hardness was also high in these coatings. MEK rubbing was increased with the increase of HPBD polyol and TMPEOTA content.

Preparation and Characterization of Tris(trimethylsiloxy)silyl Modified Polyurethane Acrylates and Their Application in Textile Treatment.

Three series of silicone modified polyurethane acrylate (SPUA) prepolymers were prepared from dicyclohexylmethane-4, 4′-diisocyanate (HMDI), PPG1000, triethylene glycol (TEG), 2-hydroxyethyl acrylate (HEA), and multi-hydroxyalkyl silicone (MI-III) with tris(trimethylsiloxy)silyl propyl side groups. Their structures were confirmed by 1H NMR, 13C NMR, and Fourier transformed infrared (FTIR) analysis, and SPUA films were obtained by UV curing. The properties of films were investigated by attenuated total reflection (ATR)-FTIR, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), water contact angle (WCA), thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), water and hexane resistance, and tensile testing. The results showed that the structures and dosages of MI-III could influence the polymerization properties, surface properties, water and n-hexane resistance, and thermal and tensile properties of SPUA. For instance, the surface aggregation of tris(trimethylsiloxy)silyl propyl groups (even ~2.5 wt%) could endow SPUA films with less microphase separation, good hydrophobicity, lipophilicity, thermal stability, and mechanical properties. Interestingly, obvious regular winkles appeared on the surfaces of SPUAIII films, which are characterized by relatively high WCA values. However, relatively smooth were observed on the surfaces of SPUAIII films, which also exhibit lower water absorption ratio values. Furthermore, the ordinary cotton textiles would be transformed into hydrophobic and oleophilic textiles after treating with SPUA simply, and they were used in the oil/water separation study. Among them, consistent with water and hexane resistance analysis of SPUA films, SPUAII treated cotton textiles are characterized by relatively small liquid absorption capacity (LAC) values. Thus, phenyl groups and side-chain tris(trimethylsiloxy)silyl propyl groups are helpful to improve the hydrophobicity and lipophilicity of SPUA films. SPUAII-5 (even with 5 wt% MII) treated cotton textiles could efficiently separate the oil/water mixture, such as n-hexane, cyclohexane, or methylbenzene with water. Thus, this material has great potential in the application of hydrophobic treatment, oil/water separation, and industrial sewage emissions, among others.

Synthesis of ultraviolet (UV)-curable water-borne polyurethane acrylate binders and comparison of their performance for pigment printing on synthetic leather

PurposeIn this study, it is aimed to synthesize ultraviolet (UV)-curable water-borne polyurethane acrylate (WPUA) binders using different types of polyols (poly (propylene glycol), PPG1000 and PPG2000 and poly (ethylene glycol), PEG1000 and PEG2000) at different molecular weights, DMPA (2,2-bis(hydroxymethyl) propionic acid) at different amounts and isophorone diisocyanate (IPDI) and use for pigment printing on synthetic leather.Design/methodology/approachUV-cured films were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC). The effect of binder structure on printing performance was determined with hardness, crock fastness, abrasion resistance and color measurements.FindingsThe highest abrasion resistance (60,000 cycles) and crock fastness values (dry crock and wet crock: 3/4) were obtained with binder PEG-C synthesized with PEG2000 and lower DMPA amount of 4.89 wt%; however, PEG-C binder showed lower hardness values. Due to lower urethane groups in PEG-C binder, more flexible films were obtained which imparted good adhesion property to printing film. Synthesized binders provided lower crock fastness and abrasion resistance properties than commercial WPUA binder.Originality/valuePigmented formulations including UV-curable water-borne synthesized PUA binder were developed and for the first time applied onto synthetic leather using screen printing method. Within this context, a new environmentally friendly printing method was proposed in this study including binder synthesis in the preparation of printing formulations.

Polyketone nanofiber: an effective reinforcement for the development of novel UV‐curable, highly transparent and flexible polyurethane nanocomposite films

AbstractThis study deals with the fabrication of a novel polyketone nanofiber‐reinforced UV‐curable polyurethane acrylate nanocomposite. An aliphatic polyketone nanofibrous mat was proficiently prepared by electrospinning using a solvent mixture of methylene chloride and trifluoroacetic acid. The outstanding characteristics of polymer nanofibers including a small pore size, a high aspect ratio and molecular orientation and an excellent mechanical performance offer the use of nanofibers as reinforcement in making nanocomposites. We fabricated a novel highly transparent and flexible nanocomposite film based on casting, electrospinning and UV‐curing processes. This method allowed significant enhancement of the mechanical properties using a very small amount (approximately 3.5 gsm) of polyketone nanofiber. The yield strength and Young's modulus of the nanocomposite were improved by up to 61% and 60%, respectively, compared to a UV‐cured polyurethane acrylate film. The reinforcing effect of nanofibers was accomplished without sacrificing the transparency and flexibility of polyurethane acrylate. The morphologies of the nanofibers and fiber–resin interface as well as the characteristics of the nanocomposite films were also studied. The effective use of nanofibers as a reinforcement and the preparation of a nanocomposite along with its characterization in comparison to a UV‐cured polyurethane acrylate film are also discussed. © 2020 Society of Chemical Industry

Synthesis and Formulation of PCL-Based Urethane Acrylates for DLP 3D Printers.

In this study, three PCL-based polyurethane acrylates were synthesized and further formulated into twelve resins for digital light processing (DLP) 3D printing. Three PCL diols with different molecular weights were synthesized via ring-opening reaction of ε-caprolactone on diethylene glycol, with the catalyst stannous octoate. Isophorone diisocyanate (IPDI) was reacted with 2-hydroxyethyl acrylate (2-HEA) and the PCL diols form PCL-based polyurethane acrylates. Twelve resins composed of different percentages of PCL-based polyurethane acrylates, poly (ethylene glycol) diacrylate (PEGDA), propylene glycol (PPG) and photo-initiator were further printed from a DLP 3D printer. The viscosities of twelve resins decreased by 10 times and became printable after adding 30% of PEGDA. The degree of conversion for the twelve resins can reach more than 80% after the post-curing process. By changing the amount of PEGDA and PPG, the mechanical properties of the twelve resins could be adjusted. PUA530-PEG-PPG (70:30:0), PUA800-PEG-PPG (70:30:0), and PUA1000-PEG-PPG (70:30:0) were successfully printed into customized tissue scaffolds. Twelve PCL-based polyurethane photo-curable resins with tunable mechanical properties, cytotoxicity, and degradability were successfully prepared. With the DLP 3D printing technique, a complex structure could be achieved. These resins have great potential for customized tissue engineering and other biomedical application.